An atomic force microscope (AFM) operates by using a probe to physically scan a surface. The probe includes a cantilever arm and a tip which contacts the sample to determine the surface characteristics. The shape of the tip determines the resolution of the scan. In general, a narrow and accurately manufactured probe tip has greater resolution than a broad and crudely manufactured probe tip.
Among the uses for AFMs is scanning surfaces such as thin-film semiconductor wafers to insure that the wafers are within manufacturing tolerances. As AFMs become more widely used in a variety of testing environments, techniques for the mass manufacture of precision probe tips become increasingly important.
A typical AFM probe tip is manufactured using a thin-film layering technique known in the semiconductor processing industry. For example, material layers are deposited, masked using conventional photolithography methods, and etched back to form a tip. Another example is where material layers are deposited through an aperture in order to create a tapered tip. A method of this type is disclosed in Zdeblick, U.S. Pat. No. 4,906,840. These techniques am time consuming and are not sufficiently precise to consistently provide high quality AFM tips.